This invention relates to .alpha.-(3-(1-phenylethenyl)phenyl)propionaldehyde which is represented by the following formula (I) and a method for producing .alpha.-(3-benzoylphenyl)propionic acid which is represented by the following formula (II) using the above new compound as an intermediate.
.alpha.-(3-(1-Phenylethenyl)phenyl)propionaldehyde is an intermediate used for economically preparing .alpha.-(3-benzoylphenyl)propionic acid (tradename: ketoprofen) which is represented by the following formula (II) and is used as a medicine for the relief of pain, fever and inflammation. ##STR1##
(2) Description of the Prior Art
With regard to the method for preparing ketoprofen, various methods have been proposed. Typical methods of them are exemplified as follows:
(1) Ketoprofen is prepared in a high yield by reacting 3-vinylbenzophenone with carbon monoxide in dilute hydrochloric acid in the presence of a palladium catalyst (U.S. Pat. No. 4,329,507). ##STR2##
(2) 3-Acetylbenzophenone is reacted with chloroform in a basic condition of tertiary ammonium salt to obtain .alpha.-arylpropenoic acid and it is then subjected to catalytic hydrogenation reduction in the presence of palladium-carbon catalyst to obtain ketoprofen (Japanese Laid-Open Patent Publication No. 55-7225). ##STR3##
In both the above methods (1) and (2), the numbers of reaction steps are small and the aimed product can be obtained in high yields. However, because it cannot be said that the synthesis of starting materials is easy, the above methods are not satisfactory in view of industrial production.